# Operators

Elf provides the following operators:

## filterNil

Filters `undefined` or `null` values:

```ts
import { filterNil } from '@ngneat/elf';

foo$.pipe(filterNil());
```

## head

Get the the first item from an array:

```ts
import { head } from '@ngneat/elf';

skills$.pipe(head());
```

## distinctUntilArrayItemChanged

A `distinctUntilChanged` implementation for arrays:

```ts
import { distinctUntilArrayItemChanged } from '@ngneat/elf';

skills$.pipe(distinctUntilArrayItemChanged());
```
